LONDON—Three men whom British prosecutors have charged with crimes related to alleged interest-rate manipulation entered "not guilty" pleas at a London court hearing Tuesday, kicking off what is likely to be more than a year of legal maneuvering leading up to a trial.

Former UBS AG and Citigroup Inc. trader Tom Hayes and former R.P. Martin Holdings Ltd. brokers Terry Farr and James Gilmour all indicated they will fight...